1) Fields of the Invention
(a)—Off power-line power supply, operating electrically in series with a high resistance/impedance.
(b)—PLC communications at the presence of an undesirable series resistance/impedance.
(c)—Automated home controls.
2) Prior art
The prior art in the field of automated homes, and in particular “smart-dimmers”, offers one of the following solutions:    (a)—Use separate wires for communications and power supplies, and leave the electrical circuit of the dimmer completely independent of communication and power supply concerns. For example, the European InstaBus also known as EIB. A pair of separate wires is used for both DC supply and communications. As seen in FIG. 7. Note that new wires are distinguished from the Existing wires.    (b)—PLC based end units, such as X-Ten technology, that requires the insertion of a third wire to the smart dimmer. See wire (406) in FIG. 5. The power-supply (407) and the Modem (408) are fed directly from the power-line using to the neutral line (406), inserted through the wall tube (401) from near the bulb to the smart dimmer, while the dimmer switching device (409), (traditionally a TRIAC), has a separate path using the existing wires (404) and (405).    (c)—U.S. Pat. Nos. 6,043,635 and 5,701,240 that suggest operating a proprietary power supply, and transmitting trough the serial impedance (lamp). The limitations of said disclosures are:            (i)—The average current available for the electronic circuitry is limited, and requires long energy accumulation times (capacitor charging) before enough stored energy is available to enable a PLC transmission.                    Attempting to draw more current, may result with undesirably lighting the bulb, at times where the dimmer should be in its Off state.                        (ii)—Illuminated displays and LED indicators are significantly disabled due to the limited average current available.        (iii)—Complex scenarios are either very slow or impossible, due to said long energy accumulation times between the many transmissions associated with said scenarios.        (iv)—Re-transmissions if required, are slow due to the long capacitor recharge times.        (v)—A PLC signal can be severely attenuated since it is transmitted through a serial resistance of a light bulb, or another load.            (d)—In order to obtain high power supply efficiency for smart dimmers that feed their internal electronics off-line, switching power supplies are traditionally used. Those normally require bulky inductors for both their operation and for filtering.
Hence making the use of said switching power supplies less cost effective, more difficult to fit into standard dimmer wall mountings, and more difficult to comply with regulatory standard noise requirements. In addition, for smart dimmers incorporating PLC capabilities, switching power supplies introduce noise into their own PLC receivers and hence compromise their sensitivity and signal to noise ratio (SNR).